This invention relates to a valve which opens upon reverse rotation of a scroll compressor to communicate gas downstream of a check valve to a location upstream of the check valve.
Scroll compressors are quite efficient, and thus are becoming more and more widely utilized in refrigerant compression applications. In general, a scroll compressor consists of a orbiting scroll having a base with a generally spiral wrap extending from the base, and a non-orbiting scroll having a base and a wrap extending from its base. The wraps of the orbiting and non-orbiting scrolls interfit to define gas pockets. As the orbiting scroll orbits relative to the non-orbiting scroll, the size of the pocket changes and an entrapped gas is compressed. Scroll compressors are designed to have the orbiting scroll orbit in one direction relative the non-orbiting scroll.
To this end, a motor for driving the orbiting scroll is connected to the orbiting scroll through a mechanical connection which changes the rotation of a motor into orbiting movement of the orbiting scroll. Frequently, the motor is provided with a three phase power supply.
If the three phase power supply is miswired, the motor may run in reverse. If the motor runs in reverse, the orbiting scroll orbits in the reverse direction relative to the non-orbiting scroll. The fluid is no longer compressed, and the systems may heat to undesirable temperatures. In addition, unwanted noise occurs.
This problem is typically encountered with a miswired three phase power supply. However, the problem can also occur with a single phase power supply where there is an intermittent shutdown. An entrapped gas can begin to drive the orbiting scroll in the wrong direction, and when the motor is again started, reverse rotation may continue.
One other concern with scroll compressors is that in some instances, the pressure differential or pressure ratio will become undesirably high. When this occurs, the discharge pressure will become correspondingly high. The prior art has addressed this problem by including separate pressure relief valves, or sensors which sense the results of the high pressure ratio or pressure differential and control the compressor accordingly. The requirement of adding in these additional valves or sensors is undesirably expensive.
It is the object of this invention to address the problem of reverse rotation, and provide a valve which reduces any harmful effects from reverse rotation.